The study of manufacturing electronic component elements and energy application components by utilizing various printing processes based on ink and paste containing metal nanoparticles is one of the megatrends in the current technology development.
An ink containing metal nanoparticles has advantages of simplifying the process by printing finely patterned metal wiring on various substrates by a single printing process such as screen printing, inkjet printing, gravure offset printing and reverse offset printing, without using a complicated process of photolithography. Further, the process simplification therefrom allows manufacturing costs to be dramatically reduced, and miniaturization of a wiring width allows a printed circuit of high density and high efficiency to be manufactured.
The present applicant noted that in a metal nanoparticle-based ink, the conductivity property of metal wiring is deteriorated by an oxide film present on the surface of metal nanoparticles, and has provided a method of synthesizing metal nanoparticles on the surface of which formation of an oxide film is controlled (International Patent Publication No. WO 2013-147535).
The present applicant deepened the study of the method of synthesizing metal nanoparticles as suggested for a long period, and as a result, found out that when distribution, they may have significantly excellent sinterability, even in the case that the surface oxidation of the metal nanoparticles occurs to some degree, and in particular, they are suitable for light sintering or laser sintering, and completed the present invention.